Ques. 1AIPMT 2015 (Cancelled)
A single compound of the structure, [figure] is obtainable from ozonolysis of which of the following cyclic compounds?
- [figure]
- [figure]
- [figure]
- [figure]
Answer
(3) [figure]
Solution
Ozonolysis cleaves the C=C bond; each doubly bonded carbon becomes C=O. A ring C=C gives one open-chain dicarbonyl compound.
Required product: CH3- O \|C-CH2- CH3 |CH-CH2-CHO (one ketone C bearing CH3, one CHO, and a CH(CH3) between two CH2 groups).
(1) gives OHC-C(CH3)2-CH2-CH2-CHO (dialdehyde)
(2) gives CH3CO-CH2CH2CH2-COCH3 (diketone)
(3) the C=C carbon with CH3 becomes CH3C=O, the other C=C carbon becomes CHO, and the ring chain CH2-CH(CH3)-CH2 joins them ⇒ exactly the given compound
(4) gives OHC-CH(CH3)-CH(CH3)-CH2-CHO
Answer: (3)